My original bug description includes some wrong details, copied from another bug. Here's the correction.
gtk2-engines-murrine is no longer needed in Debian. It was archived upstream years ago: https://gitlab.gnome.org/Archive/murrine gtk2 is on its way out of Debian. We are keeping the Adwaita and High Contrast themes until gtk2 itself is removed from Unstable. Additionally, the Debian Installer currently uses gtk2 and the Clearlooks themes so that theme is also being kept as long as the Installer uses it. None of those themes use the murrine engine. Thank you, Jeremy Bícha
